Question

11. Two trains each of length 150 m are moving in
opposite direction at 36 km/hr and 72 km/hr
respectively. Time taken by them to just cross
each other completely is
(1) 4 5
(2) 6 s
(3) 85
(4) 10 s
​

Answer 1

Answer: 10 sec

Explanation: total dist =150+150=300m

rel. vel=72+36=108km/h  (108*5/18=30m/s)

so t=d/t

300/30=10s